[Similarity of biotechnology-derived drugs: regulatory framework and specificity].

Directive 2004/27/EC, issued by the European commission specifies the conditions by which marketing approval can be awarded for a biosimilar drug, whose structure is the closest possible to that of an already marketed biotechnology-drug. This specific regulation differs in more than one point from that applied to classical generic products. Others conditions beyond the sole demonstration of in vivo bioequivalence should be satisfied to ensure prudent, i.e., without risk to the patient, therapeutic substitution.